idk if this is allowed but this dawned on me during explosives class, and its one of the greatest epiphanies I've ever had:
The conservation of energy states that energy is neither created nor destroyed, its simply changes; the same is true for mass. For example something such as a piece of wood burning. energy stored in the wood is just being released as heat and light and the mass of the ashes and the gases released equal the mass of the original piece of wood. If this is true than everything that exists in the universe right now is essentially the same that existed since the beginning of time it and will forever be just in a different form.
It's just a "simple" balanced equation, which for some reason I find very beautiful and comforting.